Add tooltips to most buttons

[bjorn3]

For several buttons I have no clue what they are supposed to do.

[Logicalshift]

Ah, very definitely on the to-do list. I need to add a way to pass them through via the UI layer: the other thing I'm experimenting with is the 'cog' icon as a way to expand anything represented as icons to a larger set of controls that explain themselves better.